A new type of lie detector test scans the eyes, to determine whether someone is lying or telling the truth.
Eye Detect is one of the crime fighting technologies on display this week at the International Association of Chiefs of Police convention in San Diego.
The test works on the premise that when you lie, it requires more mental effort.
A small, infrared eye-tracking camera looks for things like changes in the eye, size of the pupil and blink rate.
All of that then goes into an algorithm that helps determine truthfulness.
"Unless you really know the person like a mother talking to their child, it's really difficult to know whether they're lying based on where they're looking or their facial expressions," said Todd Mickelson with Converus, the company that makes Eye Detect.
"So we're measuring things that only a high powered infra red camera can measure, that can't be seen with the naked eye basically."
The detector claims to be 85 percent accurate.
Right now it's used for job screenings by a number of law enforcement agencies.
However, manufacturers say it's not as effective when used in a specific line of questioning such as a police interrogation or in identifying an unfaithful spouse.